题目描述
输入一棵二叉树,判断该二叉树是否是平衡二叉树。
平衡二叉树:
平衡二叉搜索树(Self-balancing binary search tree)又被称为AVL树(有别于AVL算法),且具有以下性质:它是一 棵空树或它的左右两个子树的高度差的绝对值不超过1,并且左右两个子树都是一棵平衡二叉树。
C++实现:
class Solution {
public:
bool IsBalanced_Solution(TreeNode* pRoot) {
if(pRoot == NULL)
return true;
return abs(getdepth(pRoot -> left) - getdepth(pRoot -> right)) <= 1 && IsBalanced_Solution(pRoot -> left) && IsBalanced_Solution(pRoot -> right);
}
int getdepth(TreeNode *p)
{
if(p == NULL)
return 0;
return 1 + max(getdepth(p -> left), getdepth(p -> right));
}
};
python实现:
# -*- coding:utf-8 -*-
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
def IsBalanced_Solution(self, pRoot):
# write code here
def getdepth(p):
if p == None:
return 0
return 1 + max(getdepth(p.left), getdepth(p.right))
if pRoot == None:
return True
return abs(getdepth(pRoot.left) - getdepth(pRoot.right)) <= 1 and self.IsBalanced_Solution(pRoot.left) and self.IsBalanced_Solution(pRoot.right)